Space station has plenty of supplies: NASA

"We have a very good backload of food, fuel and other consumables on board the ISS after the STS-135 shuttle mission," NASA spokesman Kelly Humphries told AFP.

The loss of Russia's unmanned Progress capsule, which crashed into Siberia after an upper stage launch vehicle failure about five minutes after liftoff, will require some changes to the "overall logistic but it should not have an immediate impact on the crew," he added.

"It's premature to discuss the possibility of reducing the size of the next crew. I don't anticipate that."

The supply ship had been carrying about three tons of supplies toward the orbiting research lab.

The retirement of the US space shuttle program earlier this year has left Russia as the sole nation capable of toting crew to the ISS aboard its Soyuz space capsules.

Cargo missions can also be sent to the ISS on Japan's HTV and Europe's ATV supply ships, and two such missions are scheduled for early next year.

Last month's final mission by the US shuttle Atlantis, known as STS-135, carried up more than five tons of provisions for the outpost.

"STS-135 delivered extra supplies. With those + planned ATV & HTV launches, space station will have enough supplies for all of 2012," the US space agency said in a message on the microblogging site Twitter.

"Our Russian colleagues will assess Progress data & determine root cause. Meanwhile, space station operations will continue normally."

International Space Station program manager Mike Suffredini told a press conference in Houston that the failed mission was carrying "very few one-of-a-kind items."

"We can go several months without a resupply vehicle if that becomes necessary," he said.

"There is an ability to operate station with less than six crew if that becomes necessary," he added. "Operating at a three member crew is something we are familiar with and able to do."

The crew currently aboard the ISS as part of Expedition 28 includes three Russians, two Americans and one Japanese astronaut.

The research outpost is typically staffed by six astronauts or cosmonauts on 180-day stints. The next rotation is scheduled to take place in September.

(c) 2011 AFP